This invention is concerned with improving the support systems currently available to physicians such as practicing pain management specialists wishing to perform a spinal or epidural tap, puncture or injection into the cervical or lumbar portions of the spine of a human being. In particular, this invention is concerned with minimizing lumbar lordosis, or alternatively, maximizing cervical flexion, to facilitate spinal and epidural taps, punctures, and injections.
The spinal column of a human being includes 33 bony segments called vertebrae, 24 of which are flexible. The flexible part of the spinal column includes 7 cervical vertebrae in the neck, 12 thoracic vertebrae at the back of the chest, and 5 lumbar vertebrae in the lower back. Each vertebra has a roughly cylindrical ventral part called the body, connected to which is a dorsal portion called the vertebral arch having multiple wing-like projections called spinous processes. The body and vertebral arch define a space through which the spinal cord passes. Between the bodies of adjacent vertebrae lie soft, round intervertebral disks of fibrocartilage. Numerous ligaments also connect the arches of adjacent vertebrae. The cervical, thoracic, and lumbar regions of the spine are each associated with a characteristic curve of the spine.
A spinal tap or puncture may be performed for diagnostic or therapeutic purposes. In such a procedure, a device such as a needle is inserted through the soft tissue enmeshed with and between the vertebrae of the spinal column and into the spinal canal at any appropriate level (cervical, thoracic, lumbar, or lumbo-sacral regions). In diagnostic procedures, spinal fluid can be withdrawn for study, or an injectable dye, radio-isotope tagged material, or other suitable agent may be injected to facilitate diagnostic procedures such as radiography. In therapeutic procedures, an appropriate substance can be injected into the canal. Examples of such injectable substances include pain medication (analgesics) such as narcotics, anesthetics such as lidocaine, and corticosteroids.
An epidural puncture (cervical, thoracic, lumbar, or lumbo-sacral) is similar to a spinal puncture except that the needle's target is the epidural space instead of the intrathecal space. The intrathecal space, like the epidural space, lies in the spinal canal. The intrathecal space lies deeper than the epidural space in the spinal canal, is surrounded by a thick membrane, the dura, and contains the spinal cord and cerebral spinal fluid. The epidural space is outside, or superficial to, the intrathecal space, and is the space wherein all the nerves of the spine lie just before being distributed to the arms, legs, or trunk. This space and the intrathecal space are essentially separated by the meninges.
A spinal puncture may be performed by a practitioner for a variety of reasons, including diagnostic and therapeutic measures. Some indications to perform a diagnostic puncture include clinical suspicion of meningitis or of certain diseases such as systemic lupus erythromatosis, sarcoidosis and multiple sclerosis. Therapeutic indications for spinal and epidural punctures include alleviation of pain such as pain associated with nerve root compression syndromes often accompanying vertebral disk disease.
The choices of anesthetic agents, steroids, dyes and the like for appropriate cases are within the knowledge of one of ordinary skill in the art. Similarly, the practitioner would be familiar with the choices of punctures, such as intrathecal or epidural punctures at various vertebral levels (cervical, thoracic, lumbar and sacral). The present invention is useful for all of these types of procedures.
To enhance the success of procedures that require an epidural or spinal puncture, the patient should lie in a prone position with the body not tilted to either the right or left. Moreover, it is important to flex the portion of the spinal region being treated to make it easier to negotiate the needle between the many winglike projections of the vertebrae's vertical arches and into the epidural space of the spine.
For a lumbar puncture, the natural concave curve, or lordosis, of the lumbar spine should be completely eliminated or minimized. A patient with degenerative disc disease may have a more pronounced lordosis, making it more difficult to place a needle between the vertebral bodies. To effectively place a needle into the lumbar spine, the patient should be comfortable, still, and lie in a plane as parallel to the top of the operating table as possible, and the lordosis of the lumbar spine should be reduced as much as possible.
For a cervical puncture, the patient's neck should be convexly flexed to the maximum degree. The cervical spine naturally has a slight S-shaped curve, but is almost straight if a muscular spasm is present. It is extremely difficult to place a needle between the cervical vertebrae without a great deal of cervical flexion.
For punctures at the spine's thoracic region, which is naturally curved posteriorly, increased cervical spine flexion and decreased lumbar spine lordosis may not be as critical to the success of the procedure as in cervical and lumbar spine punctures, respectively. However, the patient is likely to be more comfortable and therefore cooperative during thoracic spine punctures if the cervical spine is flexed and the lumbar lordosis is decreased. To place a needle into the thoracic epidural space, the patient should be still, comfortable, and lie in a plane parallel to the top of the operating room table. The needle is generally inserted at a largely oblique angle to the spine in order to pass between the spinous processes of the thoracic vertebrae.
Presently, a patient receiving a lumbar or cervical epidural or intrathecal injection is typically placed in a prone position on one or two standard pillows or other dome-shaped devices under either the abdomen or the chest. The pillow is usually not sufficiently dense to eliminate the lordosis of the spine. Also, a patient with a large protruding belly tends to tilt to the right or the left when using pillows. Pillows may also provide a very clumsy and uncomfortable means of positioning a patient for a cervical injection. Pillows positioned this way may be particularly uncomfortable for patients with large chests or breasts. Unfortunately, uncomfortable patients are more likely to move during the course of the therapeutic or diagnostic procedure, making it both more difficult for the physician and more dangerous to the patient.
Other devices in the prior art are believed to be encumbered with various disadvantages. One typical prone frame, often used to perform spinal surgery, is the Wilson Spinal Surgery Frame, described in and shown in FIGS. 1-4 of U.S. Pat. No. 5,584,302 to Sillaway, et al., which issued Dec. 17, 1996, which is herein incorporated by reference. The Wilson frame has two elongated, parallel panels separated by a gap and attached to a metallic frame base. After a patient lies lengthwise in a prone position over the panels, a crank is used to bow the parallel panels into a convex shape. While the Wilson frame facilitates spinal surgery, it does little to eliminate lumbar lordosis. Therefore, the frame can be uncomfortable and may be impractical for an outpatient setting.
Other prone support devices, such as those described in U.S. Pat. No. 5,613,254 to Clayman, U.S. Pat. No. 5,239,716 to Fisk, U.S. Pat. No. 5,131,106 to Jackson, U.S. Pat. No. 5,014,375 to Coonrad et al., U.S. Pat. No. 4,840,362 to Bremer, et al., and U.S. Pat. No. 4,398,707 to Cloward, include multiple pieces or moving parts which complicate the setup and operation of the frame. These frames take excessive time to operate in a busy outpatient setting. None of these frames are believed to be suitable for a cervical injection.
Other frames used by spinal surgeons and pain specialists are comprised of a plastic frame covered with a layer of gel. These frames are very hard and may interfere with breathing in a large or obese patient. Moreover, a patient will typically lie on such a frame for about 15 minutes--that is, after the doctor has already commenced the procedure--before beginning to complain of discomfort. These frames also typically lack any feature to reduce lumbar lordosis or maximize cervical flexion.
There is accordingly a need for an improved support system.